/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.webdav.transaction;

import javax.servlet.http.HttpServletResponse;

import org.apache.jackrabbit.webdav.DavException;
import org.apache.jackrabbit.webdav.xml.DomUtil;
import org.apache.jackrabbit.webdav.xml.XmlSerializable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

/**
 * <code>TransactionInfo</code> class encapsultes the information present in the
 * {@link #XML_TRANSACTIONINFO} element that forms the request body of the
 * UNLOCk request for a transaction lock.
 * 
 * @see TransactionConstants#XML_TRANSACTIONINFO
 * @see TransactionConstants#XML_TRANSACTION
 */
public class TransactionInfo implements TransactionConstants, XmlSerializable {

	private static Logger log = LoggerFactory.getLogger(TransactionInfo.class);

	private final boolean isCommit;

	/**
	 * Creates a <code>TransactionInfo</code> object
	 * 
	 * @param isCommit
	 */
	public TransactionInfo(boolean isCommit) {
		this.isCommit = isCommit;
	}

	/**
	 * Creates a <code>TransactionInfo</code> object from the given
	 * 'transactionInfo' element. The 'transactionInfo' must have the following
	 * form:
	 * 
	 * <pre>
	 * 
	 *  &lt;!ELEMENT transactioninfo (transactionstatus) &gt;
	 *  &lt;!ELEMENT transactionstatus ( commit | rollback ) &gt;
	 *  &lt;!ELEMENT commit EMPTY &gt;
	 *  &lt;!ELEMENT rollback EMPTY &gt;
	 * </pre>
	 * 
	 * @param transactionInfo
	 *            as present in the UNLOCK request body.
	 * @throws IllegalArgumentException
	 *             if the given transactionInfo element is not valid.
	 */
	public TransactionInfo(Element transactionInfo) throws DavException {
		if (transactionInfo == null
				|| !XML_TRANSACTIONINFO.equals(transactionInfo.getLocalName())) {
			log.warn("'transactionInfo' element expected.");
			throw new DavException(HttpServletResponse.SC_BAD_REQUEST);
		}
		Element txStatus = DomUtil.getChildElement(transactionInfo,
				XML_TRANSACTIONSTATUS, NAMESPACE);
		if (txStatus != null) {
			// retrieve status: commit or rollback
			isCommit = DomUtil.hasChildElement(txStatus, XML_COMMIT, NAMESPACE);
		} else {
			log
					.warn("transactionInfo must contain a single 'transactionstatus' element.");
			throw new DavException(HttpServletResponse.SC_BAD_REQUEST);
		}
	}

	/**
	 * Returns true, if this info requires a 'commit' action, false otherwise
	 * (i.e. 'rollback' is requested).
	 * 
	 * @return true if a 'commit' element was present. false otherwise.
	 * @see #XML_COMMIT
	 * @see #XML_ROLLBACK
	 */
	public boolean isCommit() {
		return isCommit;
	}

	// ------------------------------------------< XmlSerializable interface
	// >---
	/**
	 * @see org.apache.jackrabbit.webdav.xml.XmlSerializable#toXml(Document)
	 * @param document
	 */
	public Element toXml(Document document) {
		Element elem = DomUtil.createElement(document, XML_TRANSACTIONINFO,
				NAMESPACE);
		Element st = DomUtil.addChildElement(elem, XML_TRANSACTIONSTATUS,
				NAMESPACE);
		String lName = (isCommit) ? XML_COMMIT : XML_ROLLBACK;
		DomUtil.addChildElement(st, lName, NAMESPACE);
		return elem;
	}

}